But it's available to everybody in Europe regardless of what bank or other service they use.
basically friends in the same country using a select few major banks are likely to have instant sepa available between them and it seem like the normal thing, while the reality is that instant-sepa is a massive patch work of availability between countries, banks, currencies
an outsider to the EU trying to do business is unlikely to be a part of a social circle where everyone is using the same thing
theyll encounter super slow multi business day SEPA, where no bank knows where the transfer is yet, the same as ACH in the US
It's possible that it does require both banks to have implemented these instant payments. Both side have the ability to delay the transfer, but it's possible that these days they're required to support instant transactions.